Healthy Photosynthetic Mechanism Suggests ISR Elicited by Bacillus spp. in Capsicum chinense Plants Infected with PepGMV

Abstract

The aim of this study was to evaluate the effect of inoculation with Bacillus spp. isolates on the photosynthetic apparatus of Capsicum chinense plants infected with PepGMV. In vitro and greenhouse experiments were performed to evaluate whether the inoculation improved plants’ performance through the increase in photosynthetic efficiency to control PepGMV. The results showed that despite PepGMV infection, the plants inoculated with some isolates of Bacillus spp. had a healthy photosynthetic mechanism, as the photochemical parameters and gas exchange increased. The maximum photochemical quantum yield of PSII (Fv/Fm) of plants with PepGMV and inoculated with Bacillus isolates (M9, K46, and K47) increased (7.85, 7.09, and 7.77%, respectively) with respect to uninoculated controls. In inoculated plants, the CO2 assimilation rate increased and the transpiration rate decreased, therefore indicating an increased water use efficiency. This effect was reflected by the less severe symptoms caused by PepGMV in the plants obtained from seeds inoculated with different Bacillus spp. Plants inoculated with K47 isolates showed an increase in fruit yield and quality. This study suggests that it is possible to protect, at the greenhouse level, C. chinense plants from PepGMV through selected rhizobacteria inoculation.

Glomus sp. and Bacillus sp. strains mitigate the adverse effects of drought on maize (Zea mays L.)

“…Similar to the results of our experiment, Glomus increased PSII-effective efficiency in salt-stressed maize ( Xu et al, 2018 ). Moreover, literature data provide evidence that Bacillus improved Fv/Fm in Capsicum chinensis ( Samaniego-Gámez et al, 2021 ) and Euterpe oleracea ( Castro et al, 2020 ). Furthermore, the Fv/Fm ratio of Solanum lycopersicum was reduced when three Bacillus spp.…”

Induced Systemic Resistance in the Bacillus spp.—Capsicum chinense Jacq.—PepGMV Interaction, Elicited by Defense-Related Gene Expression

“…The trays were placed in a growth room (25 ± 2 • C, photoperiod of 16/8 light/dark), and they were watered every two days and leaf-fertilized weekly at a dose of 1 gL −1 (UltraFol, Biochem systems, Querétaro, México. After 18 days of germination, the seedlings were transferred into 500 mL Styrofoam cups, filled with sterile substrate, and maintained in the same controlled conditions [36].…”

“…The strains of B. cereus K46, Bacillus spp. M9 (a mixture of B. subtilis and B. amyloliquefaciens), and B. subtilis K47 were used [35,36]. All the Bacillus strains were gown in Luria-Bertoni Broth (37 • C, 24 h) under agitation.…”

“…The treatments consisted of: ( 1 [52,53]. The treated plants were grown under controlled conditions (25 ± 2 • C, photoperiod of 16/8 light/dark) for 28 days post-inoculation (dpi) with PepGMV [36].…”

“…Recent studies have shown that the ISR improves photosynthesis and favors plants under biotic stress conditions [33,34]. Specifically, our previous research has shown that Bacillus strains enhance photosystem, and furthermore, promote ISR in C. chinense plants infected with PepGMV, showing an increased CO 2 assimilation, a decrease in the transpiration rate, and increased water use efficiency, which caused less severe symptoms in PepGMV-infected plants, as well as an increase in yield and fruit quality [35,36]. In this sense, could Bacillus spp.…”